5-HT2C Receptor Structures Reveal the Structural Basis of GPCR Polypharmacology.

Drugs frequently require interactions with multiple targets-via a process known as polypharmacology-to achieve their therapeutic actions. Currently, drugs targeting several serotonin receptors, including the 5-HT2C receptor, are useful for treating obesity, drug abuse, and schizophrenia. The competing challenges of developing selective 5-HT2C receptor ligands or creating drugs with a defined polypharmacological profile, especially aimed at G protein-coupled receptors (GPCRs), remain extremely difficult. Here, we solved two structures of the 5-HT2C receptor in complex with the highly promiscuous agonist ergotamine and the 5-HT2A-C receptor-selective inverse agonist ritanserin at resolutions of 3.0 Å and 2.7 Å, respectively. We analyzed their respective binding poses to provide mechanistic insights into their receptor recognition and opposing pharmacological actions. This study investigates the structural basis of polypharmacology at canonical GPCRs and illustrates how understanding characteristic patterns of ligand-receptor interaction and activation may ultimately facilitate drug design at multiple GPCRs.

A nondegenerate code of deleterious variants in Mendelian loci contributes to complex disease risk.

Although countless highly penetrant variants have been associated with Mendelian disorders, the genetic etiologies underlying complex diseases remain largely unresolved. By mining the medical records of over 110 million patients, we examine the extent to which Mendelian variation contributes to complex disease risk. We detect thousands of associations between Mendelian and complex diseases, revealing a nondegenerate, phenotypic code that links each complex disorder to a unique collection of Mendelian loci. Using genome-wide association results, we demonstrate that common variants associated with complex diseases are enriched in the genes indicated by this "Mendelian code." Finally, we detect hundreds of comorbidity associations among Mendelian disorders, and we use probabilistic genetic modeling to demonstrate that Mendelian variants likely contribute nonadditively to the risk for a subset of complex diseases. Overall, this study illustrates a complementary approach for mapping complex disease loci and provides unique predictions concerning the etiologies of specific diseases.

Engineering covalently bonded 2D layered materials by self-intercalation.

Two-dimensional (2D) materials1-5 offer a unique platform from which to explore the physics of topology and many-body phenomena. New properties can be generated by filling the van der Waals gap of 2D materials with intercalants6,7; however, post-growth intercalation has usually been limited to alkali metals8-10. Here we show that the self-intercalation of native atoms11,12 into bilayer transition metal dichalcogenides during growth generates a class of ultrathin, covalently bonded materials, which we name ic-2D. The stoichiometry of these materials is defined by periodic occupancy patterns of the octahedral vacancy sites in the van der Waals gap, and their properties can be tuned by varying the coverage and the spatial arrangement of the filled sites7,13. By performing growth under high metal chemical potential14,15 we can access a range of tantalum-intercalated TaS(Se)y, including 25% Ta-intercalated Ta9S16, 33.3% Ta-intercalated Ta7S12, 50% Ta-intercalated Ta10S16, 66.7% Ta-intercalated Ta8Se12 (which forms a Kagome lattice) and 100% Ta-intercalated Ta9Se12. Ferromagnetic order was detected in some of these intercalated phases. We also demonstrate that self-intercalated V11S16, In11Se16 and FexTey can be grown under metal-rich conditions. Our work establishes self-intercalation as an approach through which to grow a new class of 2D materials with stoichiometry- or composition-dependent properties.

Novel insights into the multifaceted and tissue-specific roles of the endocytic receptor LRP1.

Receptor-mediated endocytosis provides a mechanism for the selective uptake of specific molecules thereby controlling the composition of the extracellular environment and biological processes. The low-density lipoprotein receptor-related protein 1 (LRP1) is a widely expressed endocytic receptor that regulates cellular events by modulating the levels of numerous extracellular molecules via rapid endocytic removal. LRP1 also participates in signalling pathways through this modulation as well as in the interaction with membrane receptors and cytoplasmic adaptor proteins. LRP1 single nucleotide polymorphisms are associated with several diseases and conditions such as migraines, aortic aneurysms, cardiopulmonary dysfunction, corneal clouding, and bone dysmorphology and mineral density. Studies using Lrp1 knockout mice revealed a critical, non-redundant and tissue-specific role of LRP1 in regulating various physiological events. However, exactly how LRP1 functions to regulate so many distinct and specific processes is still not fully clear. Our recent proteomics studies have identified more than 300 secreted proteins that either directly interact with LRP1 or are modulated by LRP1 in various tissues. This review will highlight the remarkable ability of this receptor to regulate secreted molecules in a tissue-specific manner and discuss potential mechanisms underpinning such specificity. Uncovering the depth of these "hidden" specific interactions modulated by LRP1 will provide novel insights into a dynamic and complex extracellular environment that is involved in diverse biological and pathological processes.

Real-world study of the concomitant use of biphasic insulin aspart 30/70 with GLP-1 receptor agonist versus first-generation basal insulin with GLP-1 receptor agonist in type 2 diabetes.

AIMS: Combining insulin with a glucagon-like peptide-1 receptor agonist (GLP-1RA) to treat type 2 diabetes (T2D) is common. While many studies have investigated concomitant therapy with basal insulin+GLP-1RA, few have reported on premixed insulin+GLP-1RA. We aimed to address this gap using data from the Clinical Practice Research Datalink Aurum database in England. METHODS: This retrospective cohort study with propensity score matching assessed glycaemic levels and other clinical outcomes in people with T2D, comparing biphasic insulin aspart 30/70 (BIAsp 30) + GLP-1RA with basal insulin (insulin detemir/glargine U100) + GLP-1RA (from 2006 to 2021). RESULTS: In total, 4770 eligible people were identified; 1511 had a BIAsp 30 + GLP-1RA regimen and were propensity score-matched to an equal number receiving basal+GLP-1RA. There was no significant difference in glycated haemoglobin (HbA1c) reduction between cohorts at 6 months (p = 0.15), with a decrease of -1.07 (95% CI: -1.16; -0.98) %-points (-11.7 mmol/mol [95% CI: -12.7; -10.7]) in the BIAsp 30 + GLP-1RA cohort, versus -0.97 (95% CI: -1.07; -0.88) %-points (-10.6 mmol/mol [95% CI: -11.7; -9.6]) in the basal+GLP-1RA cohort. Body mass index (BMI) decreased by -0.35 kg/m2 (95% CI: -0.52;-0.18) at 6 months with BIAsp 30 + GLP-1RA, versus -0.72 kg/m2 (95% CI: -0.90;-0.54) with basal+GLP-1RA (p = 0.003). BMI was influenced by the initiation sequence of GLP-1RA in relation to insulin (p < 0.0001). Hypoglycaemia rates were low and not significantly different between cohorts. CONCLUSIONS: Combining BIAsp 30 + GLP-1RA provides glycaemic control with no significant difference to that of propensity score-matched people receiving basal insulin+GLP-1RA, with no increase in hypoglycaemia risk or weight gain.

Repeated low doses of psilocybin increase resilience to stress, lower compulsive actions, and strengthen cortical connections to the paraventricular thalamic nucleus in rats.

Psilocybin (a classic serotonergic psychedelic drug) has received appraisal for use in psychedelic-assisted therapy of several psychiatric disorders. A less explored topic concerns the use of repeated low doses of psychedelics, at a dose that is well below the psychedelic dose used in psychedelic-assisted therapy and often referred to as microdosing. Psilocybin microdose users frequently report increases in mental health, yet such reports are often highly biased and vulnerable to placebo effects. Here we establish and validate a psilocybin microdose-like regimen in rats with repeated low doses of psilocybin administration at a dose derived from occupancy at rat brain 5-HT2A receptors in vivo. The rats tolerated the repeated low doses of psilocybin well and did not manifest signs of anhedonia, anxiety, or altered locomotor activity. There were no deficits in pre-pulse inhibition of the startle reflex, nor did the treatment downregulate or desensitize the 5-HT2A receptors. However, the repeated low doses of psilocybin imparted resilience against the stress of multiple subcutaneous injections, and reduced the frequency of self-grooming, a proxy for human compulsive actions, while also increasing 5-HT7 receptor expression and synaptic density in the paraventricular nucleus of the thalamus. These results establish a well-validated regimen for further experiments probing the effects of repeated low doses of psilocybin. Results further substantiate anecdotal reports of the benefits of psilocybin microdosing as a therapeutic intervention, while pointing to a possible physiological mechanism.

Liraglutide 3.0 mg once daily for the treatment of overweight and obesity in patients hospitalised at a forensic psychiatric department: A 26-week open-label feasibility study.

INTRODUCTION: Overweight and obesity constitute a major concern among patients treated at forensic psychiatric departments. The present clinical feasibility study aimed at investigating the extent to which glucagon-like peptide 1 receptor agonist (GLP-1RA) treatment with once-daily liraglutide 3.0 mg could be a feasible pharmacological treatment of these conditions in patients with schizophrenia spectrum disorders hospitalised in forensic psychiatry. METHODS: The 26-week, open-label feasibility study included participants aged 18-65 years diagnosed with a severe mental illness and hospitalised at a forensic psychiatric department. At the time of inclusion, all participants fulfilled the indication for using liraglutide as a treatment for overweight and obesity. Participants' baseline examinations were followed by a 26-week treatment period with liraglutide injection once daily according to a fixed uptitration schedule of liraglutide, with a target dose of 3.0 mg. Each participant attended seven visits to evaluate the efficacy and adverse events. The primary endpoint was the number of "completers", with adherence defined as >80% injections obtained in the period, weeks 12-26. Determining whether liraglutide is a feasible treatment was pre-defined to a minimum of 75% completers. RESULTS: Twenty-four participants were included in the study. Sex, male = 19 (79.2%). Mean age: 42.3 [25th and 75th percentiles: 39.1; 48.4] years; body mass index (BMI): 35.7 [31.7; 37.5] kg/m2; glycated haemoglobin (HbA1c): 37 [35; 39] mmol/mol. Eleven out of 24 participants (46%) completed the study. For the completers, the median net body weight loss after 26 weeks of participation was -11.4 kg [-15.4; -5.9]. The net difference in HbA1C and BMI was -2.0 mmol/mol [-4; -1] and -3.6 kg/m2 [-4.7; -1.8], respectively. The weight change and reduction in HbA1c and BMI were all statistically significant from baseline. CONCLUSION: The study did not confirm our hypothesis that liraglutide is a feasible treatment for a minimum of 75% of the patients initiating treatment with liraglutide while hospitalised in a forensic psychiatric department. The high dropout rate may be due to the non-naturalistic setting of the clinical trial. For the proportion of patients compliant with the medication, liraglutide 3.0 mg was an efficient treatment for overweight.

Conformational transitions of the serotonin 5-HT3 receptor.

The serotonin 5-HT3 receptor is a pentameric ligand-gated ion channel (pLGIC). It belongs to a large family of receptors that function as allosteric signal transducers across the plasma membrane1,2; upon binding of neurotransmitter molecules to extracellular sites, the receptors undergo complex conformational transitions that result in transient opening of a pore permeable to ions. 5-HT3 receptors are therapeutic targets for emesis and nausea, irritable bowel syndrome and depression3. In spite of several reported pLGIC structures4-8, no clear unifying view has emerged on the conformational transitions involved in channel gating. Here we report four cryo-electron microscopy structures of the full-length mouse 5-HT3 receptor in complex with the anti-emetic drug tropisetron, with serotonin, and with serotonin and a positive allosteric modulator, at resolutions ranging from 3.2 Å to 4.5 Å. The tropisetron-bound structure resembles those obtained with an inhibitory nanobody5 or without ligand9. The other structures include an 'open' state and two ligand-bound states. We present computational insights into the dynamics of the structures, their pore hydration and free-energy profiles, and characterize movements at the gate level and cation accessibility in the pore. Together, these data deepen our understanding of the gating mechanism of pLGICs and capture ligand binding in unprecedented detail.

I Didn't Want the Psychotic Thing to Get Out to Anyone at All: Adolescents with Early Onset Psychosis Managing Stigma.

The impact of stigmatisation on adults with mental illnesses has been thoroughly demonstrated. However, little is known about experiences of stigmatisation among adolescents with mental illness. Through semi-structured interviews with 34 Danish adolescents (14-19 years) diagnosed with psychosis, this study explores adolescents' experiences of psychosis stigma. On the basis of phenomenological analysis, we find that stigmatisation is widely experienced, and psychosis is generally regarded as more stigmatising than co-morbid mental illnesses. The participants engage in different strategies to manage possible stigma, especially strategies of (non-)disclosure. Disclosure is experienced as both therapeutic and normative, but also bears the risk of stigmatisation, and is therefore associated with numerous considerations. Being understood when disclosing is central to the participants, and lack of understanding from others is a continuous challenge. Nevertheless, participants experience benefits when feeling understood by people they confide in and can to a degree create the grounds for this through centralising aspects of their experiences of psychosis and mental illness. We argue that disclosure is both a stigma management strategy and a normative imperative, and that being understood or not is a challenge transcending stigma definitions.Clinical trial registration: Danish Health and Medicines Authority: 2612-4168. The Ethics Committee of Capital Region: H-3-2009-123. ClinicalTrials.gov: NCT01119014. Danish Data Protection Agency: 2009-41-3991.

Vaginal CO2 laser therapy for genitourinary syndrome in breast cancer survivors-VagLaser study protocol: a randomized blinded, placebo-controlled trial.

BACKGROUND: Vaginal CO2 laser therapy is a new treatment option for genitourinary syndrome of menopause. Its potential is particularly interesting in breast cancer survivors, where existing treatment options often are insufficient as hormonal treatment is problematic in these women. The objective of this study is to investigate the effectiveness of vaginal laser treatment for alleviation of genitourinary syndrome of menopause in breast cancer survivors treated with adjuvant endocrine therapy. The secondary objective is to explore the importance of repeated vaginal laser treatment and the long-term effects in this patient population. METHODS: VagLaser consist of three sub-studies; a dose response study, a randomized, participant blinded, placebo-controlled study and a follow-up study. All studies include breast cancer survivors in adjuvant endocrine therapy, and are conducted at the Department of Obstetrics and Gynecology, Randers Regional Hospital, Denmark. The first participant was recruited on 16th of February 2023. Primary outcome is vaginal dryness. Secondary subjective outcomes are vaginal pain, itching, soreness, urinary symptoms and sexual function. Secondary objective outcomes are change in vaginal histology (punch biopsy), change in vaginal and urine microbiota, and change in vaginal pH. DISCUSSION: More randomized controlled trials, with longer follow-up to explore the optimal treatment regimen and the number of repeat vaginal laser treatments for alleviation the symptoms of genitourinary syndrome of menopause in breast cancer survivors treated with endocrine adjuvant therapy, are needed. This study will be the first to investigate change in vaginal and urine microbiota during vaginal laser therapy in breast cancer survivors. TRIAL REGISTRATION: ClinicalTrials.gov: NCT06007027 (registered 22 August, 2023). PROTOCOL VERSION: Version 1, Date 13.11.2023.

ConquerFear-Group: A randomized controlled trial of an online-delivered group-based psychological intervention for fear of cancer recurrence in breast cancer survivors.

OBJECTIVE: Fear of cancer recurrence (FCR) is a distressing concern among cancer survivors. Interventions to address FCR need to be effective but also accessible and low cost. This randomized controlled trial evaluated the efficacy of an online group-based psychological intervention for FCR (ConquerFear-Group). METHODS: Eligible breast cancer (BC) survivors had completed primary treatment 3 months-5 years previously, were ≥18 years, and scored ≥22 on the Fear of Cancer Recurrence Inventory-Short Form (FCRI-SF). Participants were randomized to online ConquerFear-Group (focusing on metacognitive strategies, values-clarification, and education about follow-up behavior) or online group-based relaxation training (active control). Questionnaires were completed at baseline (T1), 1 week post-intervention (T2), three (T3) and six (T4) months later. The primary outcome was FCR (FCRI total). A number of secondary and process outcomes were also collected. Treatment effects were evaluated with mixed linear models. RESULTS: Of 866 eligible BC survivors, 475 (55%) completed the FCR screening, and 85 (18%) were randomized to ConquerFear-Group or relaxation training (2 × 6 groups). Compared with control participants, ConquerFear-Group participants experienced larger reductions in FCR (Cohen's d = 0.47, p = 0.001) and FCR severity (d = 0.57, p < 0.001), as well as mindfulness and decentering from baseline through follow-up, and improvements in emotion regulation (T2), worry (T2, T3) and rumination (T2) at some time points. CONCLUSIONS: The results demonstrated statistically significant and stable effects of ConquerFear-Group on FCR that were maintained over a 6-month period. It is suggested to investigate the program in a real-life setting, where a pragmatic trial can further demonstrate feasibility and effectiveness.

Real-world study of ethnic differences in glycaemic control and clinical characteristics among insulin-naïve people with type 2 diabetes initiating biphasic insulin aspart 30/70: A retrospective, observational cohort study in England.

AIMS: This study investigated the ethnic differences in glycaemic levels and clinical characteristics among insulin-naïve people with type 2 diabetes (T2D) initiating biphasic insulin aspart 30/70 (BIAsp 30) in primary practice in England. MATERIALS AND METHODS: Retrospective, observational cohort study utilizing data from the Clinical Practice Research Datalink Aurum database, including White, South Asian, Black and Chinese insulin-naïve adults with T2D, initiating BIAsp 30. The index date was that of the first BIAsp 30 prescription. Endpoints included change in glycated haemoglobin (HbA1c) and body mass index (BMI) 6 months post index. RESULTS: In total, 11 186 eligible people were selected (9443 White, 1116 South Asian, 594 Black, 33 Chinese). HbA1c decreased across all subgroups 6 months post index: estimated %-point changes [95% CI of -2.32 (-2.36; -2.28) (White); -1.91 (-2.02; -1.80) (South Asian); -2.55 (-2.69; -2.40) (Black); and -2.64 (-3.24; -2.04) (Chinese)]. The BMI increased modestly 6 months post index in all subgroups [estimated changes (95% CI) kg/m2 : White, 0.92 (0.86; 0.99); South Asian, 0.60 (0.41; 0.78); Black, 1.41 (1.16; 1.65); and Chinese, 0.32 (-0.67; 1.30)]. In the overall population, hypoglycaemic event rates increased from 0.92 events per 100 patient-years before the index to 3.37 events per 100 patient-years post index; event numbers were too low to be analysed by subgroup. CONCLUSIONS: Among insulin-naïve people with T2D initiating BIAsp 30, clinically meaningful HbA1c reductions in all ethnicities were observed. Some ethnic groups had larger reductions than others, but differences were small. In all groups, small BMI increases were seen, with small differences observed between groups. Hypoglycaemia rates were low.

Prognosis of breast cancer patients with brain metastasis treated with radiotherapy.

BACKGROUND: Life expectancy for patients diagnosed with metastatic breast cancer (BC) has improved in recent years, especially due to better systemic treatment. This has led to an increased incidence of brain metastases (BM), and BC is now the leading cause of BM in women. Treatment of BM primarily consists of surgery and/or radiotherapy. We aimed to investigate survival time and prognostic factors for BC patients treated with radiotherapy for BM. MATERIAL & METHODS: During the period 1st of January 2015 to 1st of June 2020, 144 consecutive BC patients treated for BM from one centre were retrospectively analyzed. The patients were either diagnosed with BM as the first metastatic lesion, or developed BM during palliative therapy for distant non-brain metastasis. The study was approved by the Central Denmark Region. RESULTS: Median age at BM diagnosis was 66 years, and 90% of the patients already had extracranial metastatic disease at BM diagnosis. Median overall survival after diagnosis of BM was 6.1 months. Short survival was observed for patients with poor performance status, leptomeningeal metastasis or more than three solid BM. Several of these factors were overrepresented in patients with estrogen receptor-positive (ER+) tumours who had poorer survival than patients with different receptor status. CONCLUSION: The number of metastatic BC patients developing BM is high, and survival following local treatment remains poor. Several prognostic factors appear to influence survival after radiotherapy. Treatment of BC patients with BM should be individualized according to performance status, leptomeningeal disease, number of BM, and receptor status of the disease.

G-quadruplex RNA motifs influence gene expression in the malaria parasite Plasmodium falciparum.

G-quadruplexes are non-helical secondary structures that can fold in vivo in both DNA and RNA. In human cells, they can influence replication, transcription and telomere maintenance in DNA, or translation, transcript processing and stability of RNA. We have previously showed that G-quadruplexes are detectable in the DNA of the malaria parasite Plasmodium falciparum, despite a very highly A/T-biased genome with unusually few guanine-rich sequences. Here, we show that RNA G-quadruplexes can also form in P. falciparum RNA, using rG4-seq for transcriptome-wide structure-specific RNA probing. Many of the motifs, detected here via the rG4seeker pipeline, have non-canonical forms and would not be predicted by standard in silico algorithms. However, in vitro biophysical assays verified formation of non-canonical motifs. The G-quadruplexes in the P. falciparum transcriptome are frequently clustered in certain genes and associated with regions encoding low-complexity peptide repeats. They are overrepresented in particular classes of genes, notably those that encode PfEMP1 virulence factors, stress response genes and DNA binding proteins. In vitro translation experiments and in vivo measures of translation efficiency showed that G-quadruplexes can influence the translation of P. falciparum mRNAs. Thus, the G-quadruplex is a novel player in post-transcriptional regulation of gene expression in this major human pathogen.

Nursing care of people with dementia in an orthopaedic acute care setting: An integrative literature review.

AIMS AND OBJECTIVES: This integrative literature review is to collect what is known about the care of people with dementia when they require a hospital admission for an orthopaedic surgical procedure and to contribute to developing an evidence-base to support nursing practice when caring for people with dementia in an orthopaedic setting. BACKGROUND: People with a dementia diagnosis are increasingly common in acute orthopaedic care settings and the admission exposes people with dementia to risks during their hospital stay. In addition, nurses find people with dementia challenging to care for due to the complexity of dual conditions. Little is known specifically about the care requirements for people with dementia in orthopaedic settings. DESIGN: Integrative literature review. METHODS: An integrative literature review and qualitative deductive content analysis using McCormack and McCance's theoretical nursing framework (Person-Centred Nursing Framework) of nine studies were undertaken. The process of the review was guided by PRISMA checklist. RESULTS: The care environment and resistance either in passive form, or through physical intervention, is common in orthopaedic nursing. Planning and delivering care for physical, cognitive and emotional needs is identified as being difficult, resulting in a lack of inclusion for patients, partly due to communication challenges. Finding ways to implement tailored care plans within standard ward routines proves difficult, and the consequence is a less than optimal care experience with adverse effects on patients characterised by an increase in dementia symptoms. CONCLUSIONS: Care for people with dementia in an orthopaedic setting is complex. It needs to be further studied so that more evidence and supporting literature can contribute to improved care for this group of patients. RELEVANCE TO CLINICAL PRACTICE: This study describes the complexity of providing fundamental care for people with dual conditions of dementia and orthopaedic injury and suggests opportunities for improvement.

The use of classic psychedelics among adults: a Danish online survey study.

BACKGROUND: Clinical studies report preliminary therapeutic effects of classic psychedelic drugs in several psychiatric conditions and international drug trends show increased use of these compounds. However, the epidemiology of classic psychedelic drug use in Scandinavian countries remains sparsely investigated. To this end, we investigated the patterns of use and the subjectively perceived acute and persisting effects of lysergic acid diethylamide (LSD), psilocybin, N,N-dimethyltryptamine (DMT), and mescaline, among Danish adults. METHODS: An anonymous online survey with 152 items was conducted using the secure survey web application REDCap. Results were presented descriptively and as comparisons between psychedelic drugs. RESULTS: Five-hundred participants (30.0% female, mean age 34.5 years) were included. Classic psychedelics were mostly used with therapeutic (28.0%) or spiritual (27.2%) intentions. Sixty-seven per cent used classic psychedelics once a year or less. Most participants (56.4%) preferred using psilocybin. Classic psychedelic use was for some individuals, associated with hazardous use of alcohol (39.4%). Among participants with a psychiatric treatment history, 80.9% reported subjective improvements in symptoms following classic psychedelic use. Participants' most memorable experiences were moderate-to-strong mystical-type experiences (MEQ30 mean ± SD 3.4 ± 1.0; range 1-5) and had positive persisting effects on well-being (mean ± SD 2.1 ± 1.0), social relationships (mean ± SD 1.7 ± 1.2), meaning of life (mean ± SD 1.9 ± 1.1), and mood (mean ± SD 1.8 ± 1.1); range -3 to 3. DMT users experienced significantly greater subjective positive effects. CONCLUSIONS: Classic psychedelics were mostly used therapeutically or spiritually and had self-reported positive persisting effects, but were also associated with hazardous use of alcohol, among Danish adults. DMT was associated with significantly greater positive effects compared to LSD and psilocybin.

Disruption of the PDZ domain-binding motif of the dopamine transporter uniquely alters nanoscale distribution, dopamine homeostasis, and reward motivation.

The dopamine (DA) transporter (DAT) is part of a presynaptic multiprotein network involving interactions with scaffold proteins via its C-terminal PDZ domain-binding sequence. Using a mouse model expressing DAT with mutated PDZ-binding sequence (DAT-AAA), we previously demonstrated the importance of this binding sequence for striatal expression of DAT. Here, we show by application of direct stochastic reconstruction microscopy not only that the striatal level of transporter is reduced in DAT-AAA mice but also that the nanoscale distribution of this transporter is altered with a higher propensity of DAT-AAA to localize to irregular nanodomains in dopaminergic terminals. In parallel, we observe mesostriatal DA adaptations and changes in DA-related behaviors distinct from those seen in other genetic DAT mouse models. DA levels in the striatum are reduced to ∼45% of that of WT, accompanied by elevated DA turnover. Nonetheless, fast-scan cyclic voltammetry recordings on striatal slices reveal a larger amplitude and prolonged clearance rate of evoked DA release in DAT-AAA mice compared with WT mice. Autoradiography and radioligand binding show reduced DA D2 receptor levels, whereas immunohistochemistry and autoradiography show unchanged DA D1 receptor levels. In behavioral experiments, we observe enhanced self-administration of liquid food under both a fixed ratio of one and progressive ratio schedule of reinforcement but a reduction compared with WT when using cocaine as reinforcer. In summary, our data demonstrate how disruption of PDZ domain interactions causes changes in DAT expression and its nanoscopic distribution that in turn alter DA clearance dynamics and related behaviors.

Quantitative proteome profiling reveals molecular hallmarks of egg quality in Atlantic halibut: impairments of transcription and protein folding impede protein and energy homeostasis during early development.

BACKGROUND: Tandem mass tag spectrometry (TMT labeling-LC-MS/MS) was utilized to examine the global proteomes of Atlantic halibut eggs at the 1-cell-stage post fertilization. Comparisons were made between eggs judged to be of good quality (GQ) versus poor quality (BQ) as evidenced by their subsequent rates of survival for 12 days. Altered abundance of selected proteins in BQ eggs was confirmed by parallel reaction monitoring spectrometry (PRM-LC-MS/MS). Correspondence of protein levels to expression of related gene transcripts was examined via qPCR. Potential mitochondrial differences between GQ and BQ eggs were assessed by transmission electron microscopy (TEM) and measurements of mitochondrial DNA (mtDNA) levels. RESULTS: A total of 115 proteins were found to be differentially abundant between GQ and BQ eggs. Frequency distributions of these proteins indicated higher protein folding activity in GQ eggs compared to higher transcription and protein degradation activities in BQ eggs. BQ eggs were also significantly enriched with proteins related to mitochondrial structure and biogenesis. Quantitative differences in abundance of several proteins with parallel differences in their transcript levels were confirmed in egg samples obtained over three consecutive reproductive seasons. The observed disparities in global proteome profiles suggest impairment of protein and energy homeostasis related to unfolded protein response and mitochondrial stress in BQ eggs. TEM revealed BQ eggs to contain significantly higher numbers of mitochondria, but differences in corresponding genomic mtDNA (mt-nd5 and mt-atp6) levels were not significant. Mitochondria from BQ eggs were significantly smaller with a more irregular shape and a higher number of cristae than those from GQ eggs. CONCLUSION: The results of this study indicate that BQ Atlantic halibut eggs are impaired at both transcription and translation levels leading to endoplasmic reticulum and mitochondrial disorders. Observation of these irregularities over three consecutive reproductive seasons in BQ eggs from females of diverse background, age and reproductive experience indicates that they are a hallmark of poor egg quality. Additional research is needed to discover when in oogenesis and under what circumstances these defects may arise. The prevalence of this suite of markers in BQ eggs of diverse vertebrate species also begs investigation.

Strychnine and its mono- and dimeric analogues: a pharmaco-chemical perspective.

Covering: up to November 2021Since its isolation in 1818, strychnine has attracted the attention of a plethora of chemists and pharmacologists who have established its structure, developed total syntheses, and examined its complex pharmacology. While numerous reviews on structure elucidation and total synthesis of strychnine are available, reports on structure-activity relationships (SARs) of this fascinating alkaloid are rare. In this review, we present and discuss structures, synthetic approaches, metabolic transformations, and the diverse pharmacological actions of strychnine and its mono- and dimeric analogues. Particular attention is given to its SARs at glycine receptors (GlyRs) in light of recently published high-resolution structures of strychnine-GlyR complexes. Other pharmacological actions of strychnine and its derivatives, such as their antagonistic properties at nicotinic acetylcholine receptors (nAChRs), allosteric modulation of muscarinic acetylcholine receptors as well as anti-cancer and anti-plasmodial effects are also critically reviewed, and possible future developments in the field are discussed.

Self-supported Pt-CoO networks combining high specific activity with high surface area for oxygen reduction.

Several concepts for platinum-based catalysts for the oxygen reduction reaction (ORR) are presented that exceed the US Department of Energy targets for Pt-related ORR mass activity. Most concepts achieve their high ORR activity by increasing the Pt specific activity at the expense of a lower electrochemically active surface area (ECSA). In the potential region controlled by kinetics, such a lower ECSA is counterbalanced by the high specific activity. At higher overpotentials, however, which are often applied in real systems, a low ECSA leads to limitations in the reaction rate not by kinetics, but by mass transport. Here we report on self-supported platinum-cobalt oxide networks that combine a high specific activity with a high ECSA. The high ECSA is achieved by a platinum-cobalt oxide bone nanostructure that exhibits unprecedentedly high mass activity for self-supported ORR catalysts. This concept promises a stable fuel-cell operation at high temperature, high current density and low humidification.